Landscaping vs. Extreme Heat

When the extreme heat of Boise summer arrives, most of us crank up the A/C & hide from the sun. Landscape plants don’t have that option. Temperatures over 90 degrees can be tough on plants, especially those not native to our area (which is most of them). To help plants make it through summer, Pro Care recommends the following actions:

Be proactive. Monitor weather forecasts & increase water frequency/duration before the heat arrives. Rule of thumb: keep soil consistently moist to a depth of 6″-8″ but not saturated. Easier said than done as there are many factors in play including soil type, sun exposure, slope, age of sprinkler system, water pressure, wind patterns, & much more. To check soil moisture, dig with a shovel, probe with a large screwdriver, or better yet invest in a core soil probe.

Visually inspect the sprinkler system every 2-4 weeks. Heads & nozzles can become clogged or go out-of-adjustment. Pressure can fluctuate. Leaks, breaks, & other malfunctions can occur suddenly. You can’t rely on the sprinkler program or soil probe alone.

Raise the mower up 1/2″ – 1″. Cutting the grass a bit taller helps quite a bit in the heat.

Limit trimming or pruning, or hold off until fall if you can. While you can trim/prune plants in the summer, it’s almost always better to do so in the fall or early spring.

Taking these steps will definitely help your plants survive the heat of summer. However, excessive heat (over 100 degrees) will test the biological thresholds of certain plants, even when you’re doing everything else well. For example, some leaves in river birch may turn yellow & fall in extreme heat. If in doubt, start by probing the soil. It should be moist but not saturated to a depth of 6″-8″.